Polyurethane coatings are widely used for applications in which a protective overcoat or film is desired. For example, two-component or so-called “2K” polyurethanes containing a polyol or polyamine first component and a polyisocyanate second component will react when mixed to form a durable film containing polyurethane or polyurea linkages. Unfortunately, 2K polyurethane coatings can have lengthy drying times. If uncatalyzed, the coating can take hours to become tack-free and days to harden completely. The hardening rate can be accelerated by adding a suitable catalyst or initiator. Although a variety of materials have been suggested for use as initiators, nowadays polyurethane coatings typically are hardened using an organometallic compound such as dibutyltin dilaurate, e.g. as in U.S. Pat. No. 6,316,535 B1.
U.S. Pat. No. 5,811,365 describes metal-containing zinc oxide compositions for use in Fischer Tropsch reactions. The zinc oxide is said to function as a support for the metal catalyst. U.S. Pat. No. 6,114,279 describes a zinc oxide-containing composition for methanol synthesis and reforming. U.S. Pat. No. 3,884,849 describes polyetherurethane foams containing, inter alia, zinc oxide and certain zinc salts. U.S. Pat. No. 6,316,535 B1 describes water-based polyurethane coating compositions containing a variety of fillers including zinc oxide.